The invention relates to an apparatus for generating shock waves directed at an area of a human or animal body to be treated using piezoelectric fibers. The piezofibers integrated in a composite material are controlled for this, and together with a control unit they form the shock-wave generating part.
Shock waves are used for different purposes in human and veterinary medicine. A medical use of these apparatuses in human medicine is lithotripsy, where the generated shock waves are focused on internal objects to be destroyed, such as kidney stones. Further applications are, for instance, inducing of bone growth, treatment of orthopaedically painful diseases (epicondylitis, calcified shoulder) and treatment of nerves, muscles and other soft-tissue structures.
The generation of shock waves using piezoelectric ceramic elements is generally known, for instance from U.S. Pat. No. 5,101,133. A multitude of piezoelectric ceramic elements are arranged on a spherical calotte and form an electro-acoustic transducer.
The arrangement of this multitude of piezoelectric ceramic elements of the known apparatus is very complex and costly as regards their production.
The piezoelectric ceramic elements are embedded in a casting compound of for instance an epoxy resin mixture.
Since the radiating surface of the piezoelectric ceramic elements covers an area of several square millimeters up to some square centimeters, the deformation of the piezoelectric ceramic elements leads to a high strain of the casting compound on the boundary layer to the ceramic elements.
Generally, the miniaturization of the structural shape of the shock-wave generating apparatus is aimed at.
This aim is pursued in order to simplify the handling of the apparatuses, on the one hand, and to open up new applications, for instance for the treatment of salivary stones, on the other hand.
In addition, it is desirable to focus the shock waves on areas having a different geometry. Freely selectable geometric forms of the shock-wave generating systems are required for this. A high efficiency for special applications is reached in this way, for instance for the treatment of long bone-fissures or cellulites.
In view of the above embodiment the invention is based on the task to provide an apparatus for generating shock waves of the type mentioned, which may be manufactured simply and cost-effectively and which may be designed reliably concerning its application and more flexibly as regards its size.